Legal claims defining the scope of protection. Each claim is shown in both the original legal language and a plain English translation.
1. A method for an automatic switching of a communication resistor of a HART device in or out, comprising: providing a HART device, including: a first interface configured to connect with a service unit; a second interface configured to connect with an electrical current loop; a microprocessor; a HART modem having a carrier detect signal, wherein the HART modem is connected to the microprocessor, including the carrier detect signal connected with the microprocessor; a communication resistor; a switch controlled by the microprocessor, wherein the switch is configured in a first state to connect the communication resistor with the second interface, and wherein the switch is configured in a second state to disconnect the communication resistor from the second interface; a filter element connected to the second interface and configured to filter out disturbance signals from a test voltage signal received via the second interface; and a comparator connected to an output of the filter element, wherein the comparator is configured to compare the filtered test voltage signal with a reference signal, and wherein an output of the comparator is connected to the microprocessor, wherein the microprocessor is configured to transmit a test signal on the electrical current loop, and to set the switch to the first state or to the second state based on the comparison of the filtered test voltage signal with the reference signal; connecting the HART device to an electrical current loop; transmitting the test signal on the electrical current loop; reading from the electrical current loop, via the second interface, the test voltage signal that is based on the transmitted test signal; filtering, via the filter element, disturbance signals from the test voltage signal; comparing, via the comparator, the filtered test voltage signal with a reference signal; and connecting the communication resistor into the electrical current loop or disconnecting the communication resistor from the electrical current loop based on the comparison of the filtered test voltage signal with the reference signal.
This invention relates to a method for automatically switching a communication resistor in or out of a HART (Highway Addressable Remote Transducer) device connected to an electrical current loop. The HART device includes a first interface for connecting to a service unit, a second interface for connecting to the current loop, a microprocessor, and a HART modem with a carrier detect signal linked to the microprocessor. The device also features a communication resistor, a switch controlled by the microprocessor, a filter element, and a comparator. The switch can connect or disconnect the communication resistor from the second interface based on microprocessor control. The filter element removes disturbance signals from a test voltage signal received via the second interface, and the comparator compares the filtered signal to a reference signal, sending the result to the microprocessor. The microprocessor transmits a test signal on the current loop, evaluates the filtered test voltage signal, and adjusts the switch state to either include or exclude the communication resistor from the loop based on the comparison. This method ensures proper communication and resistance management in HART devices by dynamically adjusting the communication resistor in response to signal conditions.
2. The method as claimed in claim 1 , wherein a preamble within a HART communication is used as the test signal.
A method for testing communication channels in industrial process control systems, particularly those using the Highway Addressable Remote Transducer (HART) protocol, addresses the challenge of ensuring reliable signal transmission in noisy or degraded environments. The method involves generating a test signal to evaluate the integrity of the communication channel before transmitting actual process data. In this specific implementation, the preamble portion of a HART communication is utilized as the test signal. The preamble, which typically consists of a known bit pattern, is transmitted over the channel, and the received signal is analyzed to assess channel quality. This approach leverages existing protocol elements to minimize additional overhead while providing a reliable means of detecting signal degradation or interference. The method may include comparing the received preamble to the expected pattern to identify errors, measure signal strength, or evaluate other performance metrics. By using the preamble as the test signal, the system can efficiently monitor channel health without requiring dedicated test signals, thereby optimizing communication efficiency and reliability in industrial automation applications.
3. The method as claimed in claim 1 , wherein the test voltage signal is filtered through a bandpass filter with a center frequency of about 1200 Hz.
This invention relates to a method for processing test voltage signals in electrical systems, particularly for improving signal quality in diagnostic or measurement applications. The method addresses the problem of noise and interference in test voltage signals, which can distort measurements and reduce accuracy in systems such as power distribution networks, industrial equipment, or electronic devices. The method involves filtering the test voltage signal through a bandpass filter with a center frequency of approximately 1200 Hz. This filtering step selectively allows frequencies around 1200 Hz to pass while attenuating unwanted frequencies outside this range, thereby reducing noise and enhancing signal clarity. The bandpass filter is designed to target the specific frequency range where the test signal is most relevant, ensuring that the filtered output is more precise and reliable for subsequent analysis or control operations. The filtering process is part of a broader method that includes generating the test voltage signal, applying it to a system under test, and measuring the response. The bandpass filter is applied to the measured response to isolate the desired signal components, improving the accuracy of diagnostic or monitoring functions. This approach is particularly useful in applications where signal integrity is critical, such as fault detection, performance testing, or calibration of electrical systems. The use of a 1200 Hz center frequency is optimized for common test scenarios, balancing signal fidelity and noise rejection.
4. The method as claimed in claim 1 , wherein the test voltage signal is filtered through a lowpass filter with a limit frequency of about 1200 Hz.
This invention relates to signal processing in electronic systems, specifically filtering test voltage signals to improve measurement accuracy. The problem addressed is the presence of high-frequency noise in test voltage signals, which can distort measurements and reduce reliability in applications such as sensor calibration, signal integrity testing, or electronic device diagnostics. The invention describes a method for filtering a test voltage signal using a lowpass filter with a cutoff frequency of approximately 1200 Hz. This filtering step removes unwanted high-frequency noise while preserving the relevant low-frequency components of the signal. The filtered signal is then used for further analysis or measurement, ensuring more accurate and stable results. The lowpass filter is designed to attenuate frequencies above 1200 Hz, which are typically associated with noise or interference in many electronic systems. By applying this filter, the method enhances signal quality, making it suitable for precise applications where noise reduction is critical. The invention may be implemented in various systems requiring clean voltage measurements, such as industrial automation, medical devices, or telecommunications equipment. The filtering process is applied to the test voltage signal before any subsequent processing steps, ensuring that the input data is free from high-frequency distortions. This approach improves the overall reliability and accuracy of the measurement system.
5. The method as claimed in claim 1 , wherein the comparing of the filtered test voltage signal with the reference signal occurs over a predefined duration and only when the filtered test voltage signal exceeds the reference signal for the predefined duration is the communication resistor connected.
This invention relates to a method for controlling the connection of a communication resistor in an electronic system, particularly in applications where signal integrity and timing are critical. The method addresses the challenge of ensuring reliable communication by preventing premature or erroneous connections of the communication resistor, which could disrupt signal transmission or cause system malfunctions. The method involves monitoring a filtered test voltage signal and comparing it to a reference signal. The comparison is performed over a predefined duration to ensure stability and accuracy. The communication resistor is only connected when the filtered test voltage signal consistently exceeds the reference signal for the entire predefined duration. This ensures that transient noise or temporary signal fluctuations do not trigger an unwanted connection, thereby improving system reliability. The filtered test voltage signal is derived from an initial test voltage signal, which may be processed through filtering to remove noise or unwanted frequency components. The reference signal serves as a threshold to determine whether the test voltage signal meets the required conditions for resistor connection. The predefined duration acts as a time window to confirm that the signal remains above the threshold long enough to justify the connection, preventing false activations. This approach enhances the robustness of communication systems by ensuring that the communication resistor is only engaged under stable and valid signal conditions, reducing errors and improving overall system performance.
6. The method as claimed in claim 1 , further comprising: disconnecting the communication resistor from the electrical current loop before the transmitting of a test signal.
This invention relates to electrical testing systems, specifically methods for improving the accuracy of test signal transmission in circuits with communication resistors. The problem addressed is the interference caused by communication resistors during test signal transmission, which can lead to inaccurate measurements or false readings. The solution involves temporarily disconnecting the communication resistor from the electrical current loop before transmitting a test signal. This ensures that the test signal is not distorted or attenuated by the resistor, allowing for more precise and reliable testing of the circuit. The method is particularly useful in industrial or automotive applications where accurate diagnostic testing is critical. By isolating the resistor during testing, the system can avoid signal degradation and obtain cleaner data for analysis. The invention may also include additional steps such as reconnecting the resistor after testing to restore normal circuit operation. This approach enhances the reliability of electrical testing procedures while maintaining the integrity of the circuit's communication functions.
7. The method as claimed in claim 1 , further comprising after the connecting of the communication resistor: verifying a carrier detect signal indicates a valid carrier signal; and if the carrier detect signal indicates no valid carrier signal, disconnecting the communication resistor from the electrical current loop.
This invention relates to communication systems, specifically methods for managing electrical current loops in communication networks to ensure reliable signal transmission. The problem addressed is the need to verify signal integrity before maintaining a connection in a communication loop, preventing unnecessary power consumption and potential signal interference when no valid carrier signal is present. The method involves connecting a communication resistor to an electrical current loop to establish a communication path. After this connection, the system verifies whether a carrier detect signal indicates a valid carrier signal. If the carrier detect signal confirms the presence of a valid carrier signal, the connection remains intact. However, if the carrier detect signal indicates no valid carrier signal, the communication resistor is automatically disconnected from the electrical current loop. This ensures that the loop is only maintained when necessary, conserving power and reducing noise in the system. The method is particularly useful in communication networks where maintaining unnecessary connections can lead to inefficiencies, such as in industrial control systems, telecommunication networks, or other applications requiring precise signal management. By dynamically adjusting the connection based on signal validity, the system optimizes performance and reliability.
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November 17, 2020
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